The present invention relates to an image forming device, and more particularly, to the device battery powered, the battery being provided in an external device such as a personal computer.
An ink jet printer ejects ink droplets onto an image recording medium such as a sheet to form an inked image on the sheet. For example, a commonly assigned co-pending U.S. Pat. No. 6,286,934 filed Sep. 24, 1998 discloses an ink jet printer provided with a PCMCIA card electrically connected to a control circuit board through a connection cable. By inserting the PCMCIA card into a PCMCIA card slot of a portable type personal computer (hereinafter simply referred to as xe2x80x9ccomputerxe2x80x9d), an electrical power can be supplied from a battery of the computer to the printer through the connection cable. AC power source is not required in such an ink jet printer. Therefore, the printer can be carried, together with the computer, to the outdoor where no AC power source is provided to perform printing operation.
However, the battery of the computer has a relatively small electrical power capacity, and therefore, only a limited amount of the electrical power can be supplied to the ink jet printer. Accordingly, if a large amount of printing is performed, electrical power in the battery of the computer may be largely consumed. Further, if the computer is battery powered, and if the large amount of printing is performed by the ink jet printer, the electrical power consumption is further promoted, and a system-down of the computer may occur.
It is therefore an object of the present invention to overcome the above described problem and to provide an improved image forming device capable of receiving electrical power from an external device such as a personal computer and capable of restraining a system-down of the external device due to electrical power consumption of the image forming device.
This and other objects of the present invention will be attained by an image forming device for use in combination with an external device, the image forming device including a printing unit, an auxiliary power source unit, detecting means and means for stopping a power supply. The printing unit normally performs an image forming operation by a primary power source installed in the external device. The auxiliary power source unit is connectable to the printing unit for supplying power to the printing unit instead of the primary power source. The detecting means detects a power supply condition of at least one of the primary power source and the auxiliary power source. The stopping means is adapted for stopping power supply from the primary power source to the printing unit in accordance with the power supply condition detected by the detecting means.
In another aspect of the invention, there is provided an image forming device for use in combination with an external device, the image forming device including a printing unit, a printer base, a detection means, and means for stopping a power supply. The printing unit normally performs an image forming operation by a primary power source installed in the external device. The printing unit has a box shaped configuration. The printer base includes a base section and a feeder section. The base section includes an auxiliary power source unit connectable to the printing unit and supplies power to the printing unit instead of the primary power source when the printing unit is mounted on the base section. The feeder section is pivotally connected to the base section and includes a sheet accommodating portion for storing therein a stack of a plurality of cut sheets and a sheet supplying mechanism that supplies each one of the sheets of the sheet stack in the sheet accommodating portion toward the printing unit. The feeder section is foldable onto the base section. The detecting means detects a power supply condition of at least one of the primary power source and the auxiliary power source. The stopping means is adapted for stopping power supply from the primary power source to the printing unit in accordance with the power supply condition detected by the detecting means.